Anecdotally, the cassette player that came with the machine had a misconfigured tape head

… Anecdotally, the cassette player that came with the machine had a misconfigured tape head. Because there was no internet nobody knew why it didn't load most of the games I got with the machine. However, saving and loading programs did work. So, I started writing programs from the user manual and game listings from some programming books I found in the library, and saving them on my cassettes. Because the user manual covered not only some tutorial BASIC but also the machine's graphics, sprites, sounds, and what other features I eventually, after getting some hang of writing BASIC, did also realize that what I could create with the machine hardware itself was virtually unlimited. I didn't necessarily know what the commands did with the underlying hardware but I knew if I poked certain numbers into certain addresses I could make my sprites appear on the screen and make them move around. …